Hours before Rondo’s MRI came back, Rivers told reporters at the Sports Authority Training Center that the guard would play in tonight’s Game 4 of the Eastern Conference semifinals against the Heat. Later yesterday, the MRI showed no fractures of the bone, meaning Rondo indeed is likely to play tonight.

The question Rivers won’t address until perhaps the first quarter tonight is whether Rondo can play effectively. He essentially used one arm in the fourth quarter of the Celtics’ 97-81 Game 3 victory at TD Garden, and the left arm could be an issue again.

“If he can’t help our team, [he won’t play],’’ Rivers said before the MRI results. “And if he can play, how well can he play and will he help or hurt our team?

“No. 1, we’re not going to hurt the player and we’re not going to do anything to hurt the team. It may not be until game time and the game until we find that out.’’

Guard Delonte West strained the back of his left shoulder Saturday night, but yesterday he said he felt better and he passed on an MRI.

“I’m optimistic about both, that they’re going to play,’’ Rivers said. “I don’t know why I am, but I am. I just don’t know how well either one can play . . . but if they’re on the floor, we’re healthy.’’

The Celtics have dealt with injuries all season and the postseason is proving no different. Center Shaquille O’Neal, who played eight minutes Saturday night, active for a game for just the second time since Feb. 1, experienced soreness in his right foot, but nothing more than anticipated.

The main concern is Rondo, who spent most of yesterday getting treatment after he reported to the training center. He was spotted eating breakfast in Waltham with no brace or restraint on his arm, and the MRI confirmed that the damage was not as severe as feared.

Rondo landed awkwardly in a scramble with Miami’s Dwyane Wade, and his left arm bent back grotesquely, causing the elbow to briefly pop out of its socket. Some saw it as Wade throwing Rondo to the floor.

“I don’t know if it was a hard foul,’’ Rivers said. “Let’s put it like this: He didn’t intend to hurt Rondo. I don’t honestly believe that 99 percent of cases in our league that the player ever intends to hurt anybody but he did. It just happens.’’

Rondo was helped to the locker room by trainer Ed Lacerte and team physician Brian McKeon, with team president Danny Ainge joining them. The group collaborated after Rondo’s elbow was popped back into place, with the point guard assuring McKeon that he could withstand the pain.

“The only [reluctance] was I told Eddie, if I see one thing, he’s out, and I mean team-wise,’’ Rivers said. “If I thought he was hurting the team, I would take him out. Listen, I played with one hand my entire career, so you can do it. Let me tell you. And he did it.’’

According to orthopedic surgeon David A. Alessandro of Excel Orthopedic Specialists in Woburn, Rondo could be limited tonight, but perhaps not as severely as expected.

“The elbow is an inherently stable joint, so once you get it back into place, people feel better, but I’m almost positive that [yesterday] and certainly over the next week or so, he’ll be pretty sore, especially when he tries to extend that elbow completely,’’ Alessandro said. “That last 10 to 20 degrees [of extending] is going to be very sore, and that’s how you can re-dislocate. I was very impressed he came back in because this is not a little thing. This is a legit injury.’’

Alessandro said dislocated elbows generally occur in wrestlers and perhaps the Celtics’ doctors would fit Rondo with a brace that would prevent full extension.

“I think if it is the routine 90 to 95 percent of normal plays in a game, I think he’s going to be fine, he’s going to be limited, but fine,’’ Alessandro said. “But it’s that 5 percent of the time . . . if he gets clipped going to the hoop, gets his legs taken out from under him, goes down breaking a fall. If that left arm is the first arm out there, that’s where the danger is going to come.

“It’s a little bit of a risk, but it’s not a 50-50 chance he’s going to dislocate his elbow.’’